STAINS AND PAINTS
Nearly every kind of surface, from drywall to concrete, needs protection from the elements. These hazardous elements can range from raging blizzards to innocent looking sunlight on a living room wall. The full total thickness of the paint that ends up on the exterior of your property is usually about one tenth the thickness of your own skin, and interior paint is even thinner. We ask a whole lot of that covering of skin. What it can do is determined by a variety of factors, including the quality and type of paint or stain, and how well the walls prepped and painted.
Paint and stain should be durable, resisting fading and abrasion and allowing repeated washings. Interior paint should go on with little spattering. An excellent interior stain or clear coating should resist fading, peeling, or yellowing, and also be easy to keep, free from impurities or waxes which could collect dirt and grime and make cleaning or recoating difficult. External paints should dry with a toughness that resists deterioration from all sorts of exposure, and an elasticity which allows for constantly expanding and contracting walls. With their thorough penetration and level of resistance to ultraviolet (UV) light, the stains and finishes on your home's outside surfaces should give a similar high performance.
A Brief History of Stain and Paint
The oldest known paint was utilized by the painters of Lascaux, who ground natural pigments with water and a binder that might have been honey, starch, or gum. You may be wondering why these cave paintings have lasted thousands of years as the paint on the south part of your home is peeling after only three winters. Here's why: The constant mild temperature, humidity, and dark interiors of caves are ideal chemical preservatives. Your home, on the other hand, is subjected to all varieties of weather and conditions.
The Egyptians knew as soon as 1000 B.C. that paint could protect as well as decorate. Beeswax, vegetable oils, and gum arabic were heated and mixed with Earth and seed dyes to paint images which have lasted thousands of years. The Egyptians used asphalt and pitch to protect their paintings. The Romans later used white lead pigment, developing a formula that could exist almost unchanged until 1950.
The Chinese used oil from the Tung tree to cement the Great Wall, and also to preserve wood. The Chinese used gums and resins to make advanced varnishes such as, shellac, turpentine, copal, and mastic. The formulas and applications for those varnishes also changed little in the following centuries.
Milk paint goes back to Egyptian times, was widely used until the late 1800’s when oil-based paints were introduced. Odorless and non-toxic, milk paint today is being revived as an excellent interior paint. Cassein, the protein in milk, dries very flat and hard, and can be tinted with other pigments. Like stains, milk paint should be covered with a wax or varnish, and is very durable.
Fashioned from hogs' bristles, badger and goat hair, brushes also transformed little for several centuries. Bristles were hand bound, rosined, and greased, then hand laced in to the stock of the brush. Hog's hair brushes, called China bristle brushes, are still a preferred brush for oil-based paints.
Pigments originally came from whatever bore a color, from ground up Egyptian mummies to road mud. Most mineral or inorganic pigments came from rust, potassium, sea salt, sulphur, alum (aluminum), and gypsum, along with others. Some extravagant works incorporated precious stones such as lapis lazuli. Hundreds of organic and natural pigments from plants, insects, and animals constructed all of those other painter's palette.
Paints and stains changed little from the time of the Pharaohs to the Industrial Revolution. A book on varnishes printed in 1773 was reprinted 14 times until 1900, with only minor revisions. However, the colder climates of northern Europe did bring about the need for more lasting paint, and in the 1500s the Dutch designer Jan van Eyck developed oil-based paint.
Starting during the Middle Ages lead, arsenic, mercury, and different acids were used as binders and color enhancers. These and other metals made the mixing and painting process dangerous. Paints and varnishes were usually mixed on site, where a ground pigment was blended with lead, oil, and solvents over sustained high heat. The maladies that arose from harmful exposure were common amongst painters at least until the late 1800s, when paint companies began to batch ready mix coatings. While contact with contaminants given off through the mixing process subsided, exposure to the harmful substances inherent in paints and stains didn't change much before 1960s, when companies ceased making lead based paints.
World War I forced the U.S. painting industry to modernize. Manufacturers had to find a replacement for the natural pigments and dyes that originated from Germany. They began to synthesize dyes. Today many pigments and dyes are chemically synthesized.
Improvements in the painting industry have extended well beyond pigments. Water-based latexes have gained in attractiveness as a safe, quality option to oil-based paints. Latexes have changed from simple "whitewashes" to highly advanced coatings that can outlast oil-based products. Both oil-based and latex coatings are emerging yearly with significant improvements, like the ground metal or glass that's now added to reflect destroying UV light.
A milestone in the evolution of coatings occurred in the very early 1990s with the introduction of a fresh category of paints and stains known as "water borne." Created by the necessity to comply with stricter regulations, water borne coatings reduce the volatile organic compounds, or VOCs, within standard paint and stains. Harmful and flammable, VOCs evaporate as a coating's solvent dries. They could be inhaled or consumed through the skin, and create ozone pollution when exposed to sunlight.
STAINS AND PAINTS... THEIR CHEMISTRY Paints and stains contain four basic types of materials: solvents, binders, pigments, and additives.
Paint and Stain Solvents and Binders
Solvents are the vehicle or medium, for the materials in a paint or stain. They regulate how fast a finish dries and exactly how it hardens. Water and alcohol are the primary solvents in latex. Oil-based solvents range from mineral spirits (thinner) to alcohols and xylene, to napthas. The solvent also includes binders, which form the "skin" when the paint dries. Binders give paint adhesion and strength. The cost of paint relies in large part upon the quality of its binder.
Because water is the vehicle in latex paint, it dries quickly, allowing for recoating the same day. The odor that you notice when by using a latex paint or stain is the "flashing," or evaporation, of the binder and solvents. The binders in latex are minute, suspended beads of acrylic or vinyl acrylic that "weld" as the paint dries. Latex enamels include a increased amount of acrylic resins for higher hardness and durability.
Alkyds and oil-based paints are basically the same thing. The word alkyd comes from "alcid," a combo of alcohol and acid that acts as the drying agent. Both have the same binders, which might include linseed, soy, or Tung oils. Oil based and alkyd enamels may contain polyurethanes and epoxies for extra hardness. Alkyd paints come in high performance combinations such as two part polyester-epoxy for professional use and a urethane customized alkyd for home use. Urethane boosts sturdiness.
Water borne coatings use a two part drying system: water is the drying agent, and oils form a hard-drying resin. These new coatings match and sometimes out perform their oil-based cousins. They resist yellowing, are more durable, require only water clean-up, have little odor, and are non-flammable. One disadvantage: They raise hardwood grain and require sanding between coats.
Paint and Stain Pigments
Pigments are the costliest component in paint. In addition to providing color, pigments also affect paint's hiding power - its capacity to protect an identical color with as few coats as possible. Titanium dioxide is the primary the most expensive ingredient in pigment. Top quality paints not only have more titanium dioxide, but also more finely ground pigment. Inexpensive paints use coarsely ground pigment, which doesn't bind well and washes off more easily.
Additives; Stain and Paint
Additives regulate how well a paint contacts, or wets, the surface. They also help paint flow, level, dry, and resist mildew. Oil is the surfactant, or wetting agent, in oil-based paint. These paints have a natural thickness and ability to flow and level; they go on smoother than latex and dry more slowly, so brush streaks have a chance to smooth out. That's why oil-based paints have a tendency to run on vertical walls more than latexes do.
Latex paint has been trying to catch up with oil-based paint over time. Today many latexes outperform oil-based paints and primers, because of thickeners, wetting agents (soapy substances that are also known as surfactants), drying inhibitors, defoamers, fungicides, and coalescents. Defoamers keep latex paint from bubbling and leaving pinpricks (called "pin holing") in the paint as it dries. Bubbling is induced when the soap wetting agent rises to the top as it dries. The better the paint, the less pin holing you will have. It used to be that if latex paint was shaken at the paint store you had to allow it to settle for a couple of hours. This is certainly no longer the truth with better paints, which can be opened up and used right from the shaker with no danger of pin holing.
Coalescents help latex resins bond, especially in colder weather. Oil-based paint, since it dries slowly and resists freezing, can stick and dry in temperatures from 50°F to 120°F. With added coalescents and, believe it or not, antifreeze, some latexes can be applied in the same heat range, and even lower. Some outdoor latexes can be properly applied at temperature at only 35°F. Companies including Pratt & Lambert, Pittsburgh Paint, and Sherwin Williams have removed the surfactants to help their latex paints be applied in lower temperature ranges. Because the wetting agents have been removed, the latex dries faster.
UV blocking chemicals have been added to paints and stains to help slow the aging process. Sunlight is responsible for much of the breakdown of any covering. It fades colors, dries paint, and increases the expansion and contraction process that makes paint crack and peel off. UV blockers in paint may consist of finely ground metals and ground glass which is currently being added for increased reflection of the sun's rays.
If you stay in a region with a lot of humidity, rainfall, and insects, you may need to consider adding a biocide or fungicide to your paint. Biocide deters insects, and fungicide counters mildew. Many coatings already contain some fungicide, but only in small concentrations because of strict interstate regulations.
Sound Quality Painting
824 90th Dr SE suite B
Lake Stevens WA 98258
(425) 512-7400
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